Electrohydraulic drawing apparatus, particularly a hoist

Abstract

An electrohydraulic drawing or hoisting apparatus for the pulling or lifting and lowering of loads, in which a load lifting member, hydraulic fluid tank, electric motor, pump, and control unit are all mounted within a single compact unit which is rigidly connected to one end of a cylinder piston unit. A control handle is connected to the hydraulic control unit so that the directions of displacement of the handle and the resulting motion of the load lifting member coincide substantially. The speed of the piston in both directions is continuously variable as a function of the displacement of the control handle. The piston's speed in at least one direction of motion, moreover, is controlled by influencing the pump delivery through displacement of the control handle. A lift ring of a vane cell pump is coupled through a connecting linkage with the control handle for influencing the pump delivery, so that zero lift position of the ring corresponds to initial or rest position of the control handle, and pump delivery flow in at least one direction corresponds to a displacement of the control handle. The pump delivery flow causes motion of the load lifting member in direction of this displacement.

Dependencies are inferred from the claim text.